Thermoplastic resins reinforced with glass fibers can exhibit improved tensile strength and excellent flexural strength, while maintaining the inherently superior moldability of the thermoplastic resins. In particular, glass fiber-reinforced thermoplastic resins can have superior flexural modulus and good heat resistance, and thus can be suitable for use in components that may be exposed to a continuous load and/or be required to withstand continuous heat. Based on these properties, glass fiber-reinforced thermoplastic resins are widely utilized in applications such as components for automobiles, electronic products, and the like.
However, glass fiber-reinforced thermoplastic resins may have drawbacks, e.g., it may be necessary to carry out injection molding at relatively higher temperatures due to significant decreases in flowability resulting from the glass fibers. Furthermore, when glass fiber-reinforced thermoplastic resins are subjected to injection molding, a difference in shrinkage ratio, e.g., between an injection direction and a vertical direction, may occur due to different orientations of the glass fibers resulting from resin flow during injection. As a result, plastic articles produced from the thermoplastic resin composition may be unintentionally bent or warped, which may deteriorate the quality of downstream products including the plastic article. In addition, glass fiber-reinforced thermoplastic resins may exhibit lower impact resistance, as compared to thermoplastic resins to which no glass fiber is added. Accordingly, they may be unsuitable for producing components that are likely to be exposed to external impacts.
In an attempt to solve problems such as reduction in impact resistance resulting from the use of glass fibers, an impact modifier, e.g., a core-shell graft copolymer, may be added to a polycarbonate resin. However, the addition of the core-shell graft copolymer may decrease flowability of the polycarbonate resin and, as a result, the glass fibers may be broken during an extrusion processes. Accordingly, there may not be enough improvement in impact resistance to achieve a desired level of impact resistance.